Other Assets - Narrative (Details) - USD ($)	3 Months Ended	5 Months Ended	7 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Jul. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Indefinite-lived Intangible Assets [Line Items]
Repurchase receivable	$ 560,000,000	$ 266,000,000		$ 560,000,000	$ 266,000,000
Goodwill impairment charge		0	$ 0	0		$ 0
Amortization expense		23,000,000	$ 2,000,000	50,000,000		$ 5,000,000
Impairment of technology and intangible assets	7,000,000
Real estate owned loans with government or GSE guarantee	11,000,000	$ 10,000,000		11,000,000	10,000,000
Pacific Union Financial, LLC
Indefinite-lived Intangible Assets [Line Items]
Repurchase receivable	$ 336,000,000			336,000,000
Addition from acquisitions				40,000,000
Intangible assets acquired				$ 13,000,000
Nationstar Mortgage Holdings Inc.
Indefinite-lived Intangible Assets [Line Items]
Addition from acquisitions					10,000,000
Intangible assets acquired					103,000,000
Assurant Mortgage Solutions Group
Indefinite-lived Intangible Assets [Line Items]
Addition from acquisitions					13,000,000
Intangible assets acquired					$ 24,000,000